Abstract
Motivated by the growing evidence for the possible lepton flavour universality violation after the first results from Fermilab's muon $(g-2)$ measurement, we revisit one of the most widely studied anomaly free extensions of the standard model namely, gauged $L_{\mu}-L_{\tau}$ model, to find a common explanation for muon $(g-2)$ as well as baryon asymmetry of the universe via leptogenesis. The minimal setup allows TeV scale resonant leptogenesis satisfying light neutrino data while the existence of light $L_{\mu}-L_{\tau}$ gauge boson affects the scale of leptogenesis as the right handed neutrinos are charged under it. For $L_{\mu}-L_{\tau}$ gauge boson mass at GeV scale or above, the muon $(g-2)$ favoured parameter space is already ruled out by other experimental data while bringing down its mass to sub-GeV regime leads to vanishing lepton asymmetry due to highly restrictive structures of lepton mass matrices at the scale of leptogenesis. Extending the minimal model with two additional Higgs doublets can lead to a scenario consistent with successful resonant leptogenesis and muon $(g-2)$ while satisfying all relevant experimental data.
Highlights
We have studied the possibility of TeV scale resonant leptogenesis in gauged Lμ − Lτ model with type I seesaw origin of light neutrino masses
While the minimal version of such a model has only one scalar singlet, we found it too constrained from light neutrino data specially if we demand two of the right-handed neutrinos to be quasidegenerate from the requirement of resonant leptogenesis
We considered the two singlet scalars version of this model and showed the possibility of TeV scale leptogenesis while satisfying light neutrino data
Summary
The recent measurement of the muon anomalous magnetic moment, aμ 1⁄4 ðg − 2Þμ=2, by the E989 experiment at Fermilab for the first time shows a discrepancy with respect to the theoretical prediction of the Standard Model (SM) [1]. Gauged lepton flavor models like Uð1ÞLμ−Lτ provide a natural origin of muon g − 2 in a very minimal setup while addressing the question of light neutrino mass simultaneously. Recent studies on this model related to muon g − 2 may be found in [7,8,9,10,11]. Motivated by the recent measurements of the muon g − 2, in this work we consider the possibility of low scale leptogenesis and constrain the Lμ − Lτ gauge sector from the requirements of successful leptogenesis and ðg − 2Þμ. A dark matter extension of the Lμ − Lτ model was found to provide a common origin of muon g − 2 and electron recoil excess reported by the XENON1T collaboration [7,11]
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